Graphs and Tables
Introduction Materials and Methods Graphs and Tables Results
Discussion Background Information Pictures References

 

Table 1:
Upper Middle elevation (Zone 3)

 

Coquina

Basalt

Species Total

Proportion of Total Number Found

Morula and Costoanachis

218

307

525

0.47

Marian’s Top (Tegula mariana)

138

162

300

0.27

Turban (Turbo fluctuosus)

75

36

111

0.10

Angelic Tooth (Acanthina angelica)

33

18

51

0.05

Fly-Specked Cerith (Cerithum stercusmuscarum)

13

24

37

0.03

Small nerita (Nerita funiculate)

24

2

26

0.02

Speckled Cerith (Cerithium maculosum)

17

16

33

0.03

Common Olive (Olivella dama)

8

1

9

0.01

Dove Shell (Columbella strombiformis)

3

4

7

0.01

Mudflat horn (Cerithidea californica mazatlanica)

3

3

6

0.01

Tower (turritella leucostoma)

2

0

2

0.0

Totals

534

573

1107

1.0

This table represents the number of snail shells found that were inhabited with hermit crabs in middle elevation (Zone 3) of the rocky intertidal zone. The crabs were collected in a time period of 20 minutess (two people collecting for 10 minutes each). Almost all of the species of hermit crabs listed are Pagrus lepidus, which is surprising to see because the common hermit species in this area is the Pagrustes anahuacus (hermit crab usually found in zone 4 at Station beach and Cedo). Collecting was done as close to the water as possible in the evening tide between 8-10 pm on Sept 29, 2007 (tide was a -3 foot tide at 8:30 pm)

 

 

Table 2:
Lower middle elevation (Zone 4 - possibly lower zone 3), Station Beach

 

Coquina

Basalt

Species Total

Proportion of Total Number Found

Costoanachis (1)

65

35

100

0.56

 Dove Shell (Columbella strombiformis)

34

16

50

0.28

Coralline (Morula ferruginosa)

8

3

11

0.06

Marian’s Top (Tegula mariana)

1

6

7

0.04

Speckled Cerith (Cerithium maculosum)

4

0

4

0.02

Striped Costoanachis (2)

2

2

4

0.02

Common Olive (Olivella dama)

1

1

2

0.01

Turban (Turbo fluctuosus)

1

0

1

0.01

Totals

116

63

179

1.0

This table represents the number of snail shells found that were inhabited with hermit crabs in low elevation (Zone 4 or lower zone 3) of the rocky intertidal zone. The crabs were collected in a time period of 20 minutes (two people collecting for 10 minutes each).The Morula and Costoanachis shells were counted as one category for time purposes and were fairly evenly divided. The common hermit crab species that was found in this area is the Clibinarius digueti (the red-fingered hermit crab usually found in zone 3 at Station beach and Cedo). Collecting was done as close to the water as possible in the evening tide between 8-10 pm on Sept 29, 2007. This zone was done first, then the zone in the table above (tide was a -3 foot tide at 8:30 pm)

 

Table 3:
Chi-Squared Test (Low and Middle Elevations: Zone 4 and 3)

 

Total Found on both Coquina and Basalt in Middle Elevation (Zone 3)

Total Expected for Middle Elevation (Zone3)

Total Found on both Coquina and Basalt in Low Elevation (Zone 4)

Total Expected for Low Elevation (Zone4)

Total Expected Numbers

Morula and Costoanachis

525

451.92

100

13.92

465.84

Marian’s Top (Tegula mariana)

300

258.24

7

0.97

259.22

Turban (Turbo fluctuosus)

111

95.55

1

0.14

95.69

Angelic Tooth (Acanthina angelica)

51

43.90

0

0.00

43.90

Fly-Specked Cerith (Cerithum stercusmuscarum)

37

31.85

0

0.00

31.85

Small nerita (Nerita funiculate)

26

22.38

0

0.00

22.38

Speckled Cerith (Cerithium maculosum)

33

28.41

4

0.56

28.96

Common Olive (Olivella dama)

9

7.75

2

0.28

8.03

Dove Shell (Columbella strombiformis)

7

6.03

50

6.96

12.99

Mudflat horn (Cerithidea californica mazatlanica)

6

5.16

0

0.00

5.16

Tower (turritella leucostoma)

2

1.72

0

0.00

1.72

Coralline (Morula ferruginosa)

0

0.00

11

1.53

1.53

Striped Costoanachis (2)

0

0.00

4

0.56

0.56

Totals

1107

952.92

179

24.92

977.83

 

Table 4:
Chi-Squared Test (continued)

 

 

X2

301.09

Degrees of Freedon

12

p

 

 

Table 5:
Overall Totals

 

Low elevation   (Zone 4)  

Middle elevation (Zone 3)

Total

Coquina

116

534

650

Basalt

63

573

636

Total

179

1107

1286

 

Fig. 1

This graph represents the number of each species of snail shell found that was inhabited by a hermit crab in low elevation (Zone 4). The two different colored bars on the graph represent the shells found on coquina rock and basalt rock. The Y-axis represents the abundance of the different species of shells found by four people in 20 minutes.

 

Fig. 2

This graph represents the number of each species of snail shell found that was inhabited by a hermit crab in low elevation (Zone 4). The two different colored bars on the graph represent the shells found on coquina rock and basalt rock. The Y-axis represents the abundance of the different species of shells found by four people in 20 minutes.

 

Fig. 3

This graph represents the number of each species of snail shell found that was inhabited by a hermit crab in middle elevation (Zone 3). The two different colored bars on the graph represent the shells found on coquina rock and basalt rock. The Y-axis represents the abundance of the different species of shells found by four people in 20 minutes.

 

Fig. 4

This graph represents the number of each species of snail shell found that was inhabited by a hermit crab on coquina rock. The two different colored bars on the graph represent the shells found in middle elevation (Zone 3) and low elevation (Zone 4). The Y-axis represents the abundance of the different species of shells found by four people in 20 minutes.

 

Fig. 5

This graph represents the number of each species of snail shell found that was inhabited by a hermit crab on basalt rock. The two different colored bars on the graph represent the shells found in middle elevation (Zone 3) and low elevation (Zone 4). The Y-axis represents the abundance of the different species of shells found by four people in 20 minutes.

 

Fig. 6


Fig. 7

Fig. 8

Fig. 9

 

 

 
 
Authors: Jenessa Hill & Jennifer Mordaunt| Ecology 450| Marine Discovery| Created November 20,2007| University of Arizona| Class photos